Latest news with #YaraHaridy
Observer
24-05-2025
- Science
- Observer
Teeth hurt? It could be because of a 500-million-year-old fish
Ever wondered why our teeth are so sensitive to pain or even just cold drinks? It might be because they first evolved for a very different purpose than chewing half a billion years ago, a study suggested Wednesday. The exact origin of teeth -- and what they were for -- has long proved elusive to scientists. Their evolutionary precursors are thought to be hard structures called odontodes which first appeared not in mouths but on the external armour of the earliest fish around 500 million years ago. Even today, sharks, stingrays and catfish are covered in microscopic teeth that make their skin rough like sandpaper. There are several theories for why these odontodes first appeared, including that they protected against predators, helped with movement through the water or stored minerals. But the new study published in the journal Nature supports the hypothesis that they were originally used as sensory organs which transmitted sensations to nerves. At first, the study's lead author Yara Haridy was not even trying to hunt down the origins of teeth. Instead the postdoctoral researcher at the University of Chicago was probing another major question puzzling the field of palaeontology: what is the oldest fossil of an animal with a backbone? Haridy asked museums across the United States to send her hundreds of vertebrate specimens -- some so small they could fit on the tip of a toothpick -- so she could analyse them using a CT scanner. She began focusing on dentine, the inner layer of teeth that sends sensory information to nerves in the pulp. - Things get fishy - A fossil from the Cambrian period called Anatolepis seemed to be the answer she was looking for. Its exoskeleton has pores underneath the odontodes called tubules that could indicate they once contained dentine. This has previously led paleontologists to believe that Anatolepis was the first known fish in history. But when Haridy compared it to the other specimens she had scanned, she found that the tubules looked much more like sensory organs called sensilla of arthropods, a group of animals that includes crustaceans and insects. The mighty Anatolepis was therefore demoted to the rank of an invertebrate. For modern arthropods such as crabs, scorpions and spiders, sensilla are used to perceive temperature, vibration and even smell. How little these features have changed over time suggests they have been serving these same functions for half a billion years. The researchers said they found "striking" similarities between these features in Anatolepis and vertebrate fish from around 465 million years ago -- as well as some better-known fish. "We performed experiments on modern fish that confirmed the presence of nerves in the outside teeth of catfish, sharks and skates," Haridy told AFP. This shows that "tooth tissues of odontodes outside the mouth can be sensitive -- and perhaps the very first odontodes were as well," she added. "Arthropods and early vertebrates independently evolved similar sensory solutions to the same biological and ecological problem." Senior study author Neil Shubin, also from the University of Chicago, said that these primitive animals evolved in "a pretty intense predatory environment". "Being able to sense the properties of the water around them would have been very important," Shubin said in a statement. Haridy explained that over time, fish evolved jaws and "it became advantageous to have pointy structures" near their mouth. "Little by little some fish with jaws had pointy odontodes at the edge of the mouth and then eventually some were directly in the mouth," she said. "A toothache is actually an ancient sensory feature that may have helped our fishy ancestors survive!" —AFP
Yahoo
23-05-2025
- Science
- Yahoo
Human Teeth Evolved From Body Armor of Extinct Species
A new study, published on May 21 in the journal Nature, has revealed surprising information about the origins of human teeth. Our teeth evolved from the piercing 'body armor' of extinct fish, which existed about 465 million years ago. The study explained how sensory tissue found within the exoskeletons of the fish can be tied to the same "genetic toolkit" that comprises human teeth. "This shows us that 'teeth' can also be sensory even when they're not in the mouth," Yara Haridy, the study's co-author, said in a information came as a surprise to Haridy and her fellow researchers, who initially wanted to find the oldest vertebrate fossil ever recorded. Vertebrate fossils can typically be identified because they contain internal tubules which store dentine, the calcified tissue which is found under the enamel of human teeth. Dentine is also found inside the external bumps on the armor of ancient fishes. While analyzing the 'first fish' species, Anatolepis heintzi, scientists found what appeared to be large pores filled with dentine. They compared the fossil to several ancient and modern animals, but upon further inspection, they found the pores to be more similar to the sensory organs which crabs have on their shells. That means Anatolepis heintzi is an invertebrate arthropod rather than a vertebrate were astonished to discover that fish and ancient arthropods produce the same type of mineralized tissue. They believe that human teeth began evolving into their modern form around 460 million years ago after animals utilized the same "genetic toolkit" to make their teeth. "Viewed through this evolutionary lens, the fact that teeth in the mouth are extremely sensitive is less of a mystery, and more a reflection of their evolutionary origins within the sensory armor of early vertebrates," the study Teeth Evolved From Body Armor of Extinct Species first appeared on Men's Journal on May 23, 2025
Yahoo
23-05-2025
- Science
- Yahoo
Your Teeth May Have Evolved From Ancient Fish Armor
The next time you wince from an ice-cold drink or a too-hot slice of pizza, blame your ancestors. Specifically, the armor-plated fish that swam Earth's oceans over 460 million years ago. A new study published in Nature traces the evolutionary origin of human teeth to sensory structures found on the exoskeletons of extinct fish. Researchers say the same "genetic toolkit" that creates dentine—the hard, sensitive tissue beneath the enamel in modern teeth—was first used by ancient sea creatures to sense their environment. 'This shows us that 'teeth' can also be sensory even when they're not in the mouth,' said study co-author Yara Haridy, a paleontologist at the University of Chicago. The breakthrough came when scientists were analyzing fossilized remains of jawless fish like Anatolepis heintzi using high-resolution CT scans. While initially thought to be early vertebrates based on their dentine-like structures, the team found something surprising: sensory pores resembling those in the shells of crabs, not fish. That reclassification helped clarify something bigger. Both early arthropods and early vertebrates were developing mineralized sensory tissues in their armor. Eventually, those same tissues evolved into something more internal, refined, and, millions of years later, familiar: human CT scans also captured vivid detail in species like Astraspis, revealing dentine-filled tubules and vascular networks, showing how these ancient sensors were wired into the nervous system. The similarities to today's dental structures are striking. 'Viewed through this evolutionary lens, the fact that teeth in the mouth are extremely sensitive is less of a mystery,' the authors wrote. 'It's a reflection of their evolutionary origins within the sensory armor of early vertebrates.' In short, your teeth are the last echo of a prehistoric defense system designed not to chew, but to Teeth May Have Evolved From Ancient Fish Armor first appeared on Men's Journal on May 22, 2025
Time of India
22-05-2025
- Science
- Time of India
The secret history of teeth revealed: How they originated inside a 465-million-year-old fish's body
Our knowledge about the origins of teeth pertains to that of the entire body, a natural occurrence made up of tissues. But did you know that human teeth evolved from the "body armour" of an extinct fish that lived 465 million years ago? From vertebrates to teeth In a published in the journal Nature on Wednesday, researchers showed how sensory tissue discovered on the exoskeletons of ancient fish is linked to the same "genetic toolkit" that produces human teeth. Tired of too many ads? go ad free now "This shows us that 'teeth' can also be sensory even when they're not in the mouth," said Yara Haridy, co-author of the study and palaeontologist and evolutionary biologist at the University of Chicago. Initially, researchers set out to identify the earliest vertebrate in the fossil record seeking specimens from the Cambrian and Ordovician periods. An obvious sign of a vertebrate species is the presence of internal tubules for dentine, a calcified tissue that is found under the enamel in the human teeth, but also in the external bumps or odontodes in ancient fish armour. While making the use of high-resolution CT scans to analyse the jawless "first fish" species Anatolepis heintzi, the researchers discovered pores filled with dentine. They also compared the fossil to a coterie of ancient fossils and modern marine life. The shocking discovery Upon closer investigations, researchers realised that the supposed dentine-lined pores were like the sensilla, the sensory organs on the shells of crabs, thus making A. Heintz, an ancient invertebrate arthropod and not a vertebrate fish. Vertebrates and invertebrates, both have sensory armours connected to nerves that help them sense their environment. To substantiate the discovery that the fish was an arthropod, the team scanned fossils and modern specimens from snails and barnacles to sharks and catfish. It was revealed that the suckermouth catfish raised in Hardy's own lab had small tooth-like scales on their skin, called denticles, that were connected to nerves. Tired of too many ads? go ad free now This discovery also led to the realisation that ancient vertebrates had the same mineralized tissue that evolved into dentine and then our sensitive teeth. These tissues helped them sense their environment like cold waters or pressure from nearby objects, just like our teeth. Thus, this study also supports a key theory in evolutionary biology called the "outside-in" hypothesis where sensory structures evolved on exoskeletons at least 460 million years ago and were used by animals to make teeth. "Viewed through this evolutionary lens, the fact that teeth in the mouth are extremely sensitive is less of a mystery, and more a reflection of their evolutionary origins within the sensory armour of early vertebrates," wrote the researchers in the study.
Yahoo
22-05-2025
- Science
- Yahoo
Tooth pain's origins traced to 465-million-year-old armored fish with sensors
Ever wonder why teeth hurt? Blame it on a prehistoric armored the outer layer of our teeth is coated in hard enamel, it's the inner layer, called dentine, that feels pain. Dentine carries signals to the nerves when we bite into something hard, or feel the sting of ice cream or sweetness. Scientists have long debated where teeth came from. One idea was that they evolved from small bumps on the tough outer shells of ancient fish. These bumps, known as odontodes, were once a mystery. But now, a new study confirms that these structures in an early vertebrate fish from the Ordovician period, about 465 million years ago, contained dentine. Using 3D scans on fossils of the fish, researchers discovered that these bumps were sensitive and were likely used to sense their environment, like detecting cold water or pressure from nearby objects. While studying the fossils, the team also found that odontodes in ancient fish looked a lot like sensilla — tiny sensory organs found in the shells of animals like crabs and shrimp. Sensilla are also seen in fossils of ancient invertebrates. Surprisingly, these two features evolved in completely different animal groups: fish, which have backbones, and arthropods, which don't. According to Dr. Yara Haridy, who led the study, this is a classic case of evolutionary convergence — when different species develop similar traits on their own. 'These jawless fish and Aglaspidid arthropods (extinct marine arthropods) have an extremely distant shared common ancestor that likely had no hard parts at all,' Haridy said. 'We know that vertebrates and arthropods evolved hard parts independently and amazingly they evolved similar sensory mechanisms integrated into their hard skeleton independently.' The findings also help explain a long-standing mix-up in the fossil record. For decades, a Cambrian-era fossil called Anatolepis was thought to be one of the earliest vertebrates, thanks to tooth-like bumps on its surface. But when the researchers closely examined the fossil using high-resolution CT scans, they realized those bumps didn't contain dentine after all. Instead, they looked just like the sensory structures — sensilla — seen in arthropods. That meant Anatolepis wasn't a vertebrate fish, but likely an ancient arthropod. The confusion, it turns out, is understandable. Sensory armor evolved in both vertebrates and invertebrates, and it often looks strikingly similar under the microscope. That's because both groups developed ways to sense their environment using nerve-connected structures embedded in hard outer coverings — whether it was fish skin or crab shell. To compare these features more broadly, the team scanned fossils and modern specimens ranging from snails and barnacles to sharks and catfish. One discovery stood out: suckermouth catfish raised in Haridy's own lab had small tooth-like scales on their skin — called denticles — that were directly connected to nerves. These denticles, like the ancient odontodes and arthropod sensilla, weren't just armor — they were sensory tools. 'We think that the earliest vertebrates, these big, armored fish, had very similar structures,' Haridy said. 'They look the same in ancient and modern arthropods because they're all making this mineralized layer that caps their soft tissue and helps them sense the environment.' This research also adds weight to a key theory in evolutionary biology. Called the "outside-in" hypothesis, the theory suggests that teeth evolved from external sensory structures like these. In other words, long before animals had mouths full of teeth, they had sensitive armor that helped them survive. While they didn't pin down the earliest vertebrate fish, Neil Shubin, the senior author of the study, said this discovery was more than worth the effort. 'For some of these fossils that were putative early vertebrates, we showed that they're not. But that was a bit of misdirection,' he said. 'We didn't find the earliest one, but in some ways, we found something way cooler.' The study has been published in the journal Nature.
